Method and apparatus for monitoring physiological conditions

Abstract

The invention concerns a physiological monitoring device that, in one embodiment, comprises a capacitive sensor. The sensor comprises a first plate, a second plate and a dielectric medium coupled to the first plate and second plate. A power source charges the sensor to generate an initial capacitance. A band couples the sensor to a blood vessel of a patient. For example, the blood vessel can be located in the umbilical cord of a human baby. An impulse from the blood vessel exerts pressure against the second plate of the sensor and consequently generates a first capacitance. A controller monitors the patient's physiological measurement by detecting the generation of the first capacitance.

1. A method for determining a physiological measurement comprising the following steps:
 bounding a capacitive sensor to a pulsating blood vessel of an umbilical cord of a patient; 
 said sensor including a first plate, a second plate, and a dielectric medium operatively coupled to said first plate and said second plate; 
 said dielectric medium including a material that enables said first plate and said second plate to move relative to one another when pressure from said pulsating blood vessel is exerted on said second plate; 
 detecting a first capacitance generated in response to a first pressure from a first pulse from said pulsating blood vessel; wherein said first pressure is exerted against said second plate of said sensor; and 
 detecting a physiological measurement of said patient, by a controller, in response to detecting said first capacitance. 
 
     
     
       2. The method of  claim 1 , wherein said step of detecting said physiological measurement includes detecting a blood pressure of said patient. 
     
     
       3. The method of  claim 2 , wherein said step of detecting said blood pressure is performed for more than 1 hour in a substantially continuous manner. 
     
     
       4. The method of  claim 2 , wherein said step of detecting said blood pressure further comprises the following steps:
 detecting a second capacitance generated in response to a second pressure from a second pulse from said pulsating blood vessel, wherein said second pressure is exerted against said second plate of said sensor; and 
 detecting said blood pressure using a moving window comprised of said first capacitance and said second capacitance. 
 
     
     
       5. The method of  claim 1 , wherein said step of operatively coupling said capacitive sensor to said pulsating blood vessel is performed non-invasively. 
     
     
       6. The method of  claim 1 , wherein said step of detecting said physiological measurement includes detecting a pulse rate of said patient. 
     
     
       7. The method of  claim 6 , further comprising the following steps:
 detecting a second capacitance generated in response to a second pressure from a second pulse from said pulsating blood vessel, wherein said second pressure is exerted against said second plate of said sensor; and 
 detecting said pulse rate in response to detecting said first capacitance and detecting said second capacitance. 
 
     
     
       8. The method of  claim 1 , wherein said pulsating blood vessel is substantially located in a part of the patient's body chosen from the group consisting of said patient's head, arm, torso and leg. 
     
     
       9. One or more program storage media readable by a machine and containing instructions for performing the following steps of the method contained in  claim 1 :
 detecting a first capacitance generated in response to a first pressure from a first pulse from said pulsating blood vessel; wherein said first pressure is exerted against said second plate of said sensor; and 
 detecting a physiological measurement of said patient in response to detecting said first capacitance. 
 
     
     
       10. The method of  claim 1 , further comprising the following steps:
 impressing an electric potential across said first and second plates of said sensor; and 
 detecting an initial capacitance generated in response to said step of impressing said potential across said first and second plates of said sensor. 
 
     
     
       11. A method for determining a physiological measurement comprising the following steps:
 operatively coupling a capacitive sensor to a pulsating blood vessel of a patient; 
 said sensor including a first plate, a second plate, and a dielectric medium operatively coupled to said first plate and said second plate; 
 said dielectric medium including a material that enables said first plate and said second plate to move relative to one another when pressure from said pulsating blood vessel is exerted on said second plate; 
 detecting a first capacitance generated in response to a first pressure from a first pulse from said pulsating blood vessel; wherein said first pressure is exerted against said second plate of said sensor; 
 detecting a physiological measurement of said patient by a controller in response to detecting said first capacitance, wherein said step of detecting said physiological measurement includes detecting a blood pressure of said patient; 
 detecting a baseline blood pressure (Baseline BP) using a manometer; 
 detecting a first minimum capacitance generated in response to said first pressure; 
 detecting a first maximum capacitance generated in response to said first pressure; 
 detecting a baseline peak-to-peak blood pressure (Baseline peak-to-peak BP) by determining a difference between said first minimum capacitance and said first maximum capacitance; 
 detecting a second minimum capacitance generated in response to a second pressure from a second pulse from said pulsating blood vessel, wherein said second pressure is exerted against said second plate of said sensor; 
 detecting a second maximum capacitance generated in response to said second pressure; 
 detecting a new peak-to-peak blood pressure (New peak-to-peak BP) by determining a difference between said second minimum capacitance and said second maximum capacitance; and 
 detecting a new blood pressure of said patient (New BP) from the equation: (New BP)=(Baseline BP)*(New peak-to-peak BP)/(Baseline peak-to-peak BP). 
 
     
     
       12. A method for determining a physiological measurement comprising the following steps:
 operatively coupling a capacitive sensor to a pulsating blood vessel of a patient; 
 said sensor including a first plate, a second plate, and a dielectric medium operatively coupled to said first plate and said second plate; 
 said dielectric medium including a material that enables said first plate and said second plate to move relative to one another when pressure from said pulsating blood vessel is exerted on said second plate; 
 detecting a first capacitance generated in response to a first pressure from a first pulse from said pulsating blood vessel; wherein said first pressure is exerted against said second plate of said sensor; and 
 detecting a physiological measurement of said patient by a controller in response to detecting said first capacitance; 
 wherein said pulsating blood vessel is substantially located in said patient's umbilical cord. 
 
     
     
       13. A system comprising:
 one or more memory units operable for storing one or more computer program products for detecting a physiological measurement; 
 one or more processors coupled to the one or memory units, wherein the one or more processors execute the one or more computer program products for performing the steps of:
 detecting a first capacitance generated in response to a first pressure from a first pulse from a pulsating blood vessel of a patient; wherein said first pressure is exerted against a capacitive sensor that is operatively coupled to said pulsating blood vessel; 
 detecting a physiological measurement of said patient in response to detecting said first capacitance, wherein said step of said one or more processors executing the one or more computer products for detecting said physiological measurement includes detecting a blood pressure of said patient; 
 storing a baseline blood pressure (Baseline BP) detected using a manometer; 
 detecting a first minimum capacitance generated in response to said first pressure; 
 detecting a first maximum capacitance generated in response to said first pressure; 
 detecting a baseline peak-to-peak blood pressure (Baseline peak-to-peak BP) by determining a difference between said first minimum capacitance and said first maximum capacitance; 
 detecting a second minimum capacitance generated in response to a second pressure from a second pulse from said pulsating blood vessel, wherein said second pressure is exerted against said sensor 
 detecting a second maximum capacitance generated in response said second pressure; 
 detecting a new peak-to-peak blood pressure (New peak-to-peak BP) by determining a difference between said second minimum capacitance and said second maximum capacitance; and 
 detecting a new blood pressure of said patient (New BP) from the equation: (New BP)=(Baseline BP)*(New peak-to-peak BP)/(Baseline peak-to-peak BP).